Added TSC passthrough specification to time handling

[palacios.releases.git] / palacios / src / palacios / vmm_time.c

diff --git a/palacios/src/palacios/vmm_time.c b/palacios/src/palacios/vmm_time.c
index ce89b21..5b3bfe7 100644 (file)
--- a/palacios/src/palacios/vmm_time.c
+++ b/palacios/src/palacios/vmm_time.c
@@ -314,7 +314,7 @@ static int tsc_msr_write_hook(struct guest_info *info, uint_t msr_num,
 
 static int
 handle_time_configuration(struct v3_vm_info * vm, v3_cfg_tree_t *cfg) {
-    char *source, *dilation;
+    char *source, *dilation, *tsc;
 
     vm->time_state.flags = V3_TIME_SLAVE_HOST;
     vm->time_state.td_num = vm->time_state.td_denom = 1;
@@ -332,6 +332,19 @@ handle_time_configuration(struct v3_vm_info * vm, v3_cfg_tree_t *cfg) {
        }
     }
 
+    // Should we make a separate TSC device that handles this sort of thing?
+    tsc = v3_cfg_val(cfg, "tsc");
+    if (tsc) {
+       if (strcasecmp(tsc, "host") == 0) {
+           if (!(vm->time_state.flags & V3_TIME_SLAVE_HOST)) {
+               PrintError("WARNING: Guest TSC set to passthrough host TSC, but guest time not slaved to host time.");
+           }
+           vm->time_state.flags |= V3_TIME_TSC_PASSTHROUGH;
+       } else if (strcasecmp(source, "guest") != 0) {
+           PrintError("ERROR: Unknown TSC configuration in time configuration.\n");
+       }
+    }
+
     dilation = v3_cfg_val(cfg, "dilation");
     if (dilation) {
         if (!(vm->time_state.flags & VM_TIME_SLAVE_HOST)) {
@@ -450,10 +463,18 @@ void v3_init_time_core(struct guest_info * info) {
     if (info->vm_info->time_state.flags & V3_TIME_SLAVE_HOST) {
        time_state->flags |= VM_TIME_SLAVE_HOST;
     }
+    if (info->vm_info->time_state.flags & V3_TIME_TSC_PASSTHROUGH) {
+       time_state->flags |= VM_TIME_TSC_PASSTHROUGH;
+    }
+
     if ((time_state->clock_ratio_denom != 1) ||
        (time_state->clock_ratio_num != 1) ||
        (info->vm_info->time_state.td_num != 1) || 
        (info->vm_info->time_state.td_denom != 1)) { 
+       if (time_state->flags | VM_TIME_TSC_PASSTHROUGH) {
+           PrintError("WARNING: Cannot use reqested passthrough TSC with clock or time modification also requested.\n");
+           time_state->flags &= ~VM_TIME_TSC_PASSTHROUGH;
+       }
        time_state->flags |= VM_TIME_TRAP_RDTSC;
     }
 
@@ -466,9 +487,11 @@ void v3_init_time_core(struct guest_info * info) {
               info->vm_info->time_state.td_denom, 
               time_state->clock_ratio_num, time_state->clock_ratio_denom,
               time_state->ipc_ratio_num, time_state->ipc_ratio_denom);
-    PrintDebug("    source = %s, rdtsc trapping = %s\n", 
+    PrintDebug("    time source = %s, tsc handling =  %s\n", 
               (time_state->flags & VM_TIME_SLAVE_HOST) ? "host" : "none",
-              (time_state->flags & VM_TIME_TRAP_RDTSC) ? "true" : "false");
+              (time_state->flags & VM_TIME_TSC_PASSTHROUGH) ? "passthrough" 
+                  : (time_state->flags & VM_TIME_TRAP_RDTSC) ? "trapping" 
+                      : "offsettting");
 
     time_state->guest_cycles = 0;
     time_state->tsc_guest_offset = 0;